Each is adapted for the special conditions found in Washington and in the ocean.
There are approximately 624 “populations” of salmon in Washington. A population is a scientifically designated group (Lower Columbia River Spring Chinook, Skagit River coho) that is adapted to live in the special conditions of our state’s rivers and estuaries.

Coho and sockeye are found in freshwater year-round; coho in small coastal streams and sockeye in lakes. These fish are very susceptible to poor water quality, such as high temperatures and pollution.

Salmon species have adapted to use virtually every part of every stream in the northwest.

Big rivers are used by pink salmon in the lower reaches, chinook in the mainstem and larger tributaries, coho in small tribs, and steelhead in the uppermost tributaries.

Small streams are used by chum in the lower reaches, coho next, and cutthroat in the headwaters.

A moving fry is much easier to see than a motionless one. This is why salmon tend to spawn in parts of the stream that their offspring use for rearing; the emerging fry do not have to travel far to find rearing areas.

The size of a salmon is usually related to its age. Pink salmon are the smallest fall-spawning salmon and are also the youngest, at two years. Chinook can live up to nine years, the longest, which is why some chinook can grow to over 100 pounds. Cutthroat, which live longer than pinks, are smaller because they live in less productive areas of the watershed.

There is a sixth fall-spawning salmon, the masu, or cherry salmon, which is found only in Asia. This fish occupies the same niche that the sea-run cutthroat trout occupies in North America.

Steelhead and rainbow trout are the same species of fish; rainbow are the freshwater form, and steelhead the anadromous form.

Steelhead and cutthroat trout were recently added to the salmon genus, Oncorhynchus, from the trout genus, Salmo. Also, the scientific name of steelhead changed from Salmo gairdneri to Oncorhynchus mykiss.